PSS Shaft Seal problems

[Tranona]

So can anyone tell me where to get an old-fashioned bronze stuffing box that takes packing ? There seem to have been occasional issues with all the more modern seals and Sunrunner has a keel-stepped mast so never has perfectly dry bilges in any case : a few drops a minute more won't hurt.

Boo2

Plenty of suppliers such as T Norris, Lake Engineering. However, better to use one of the modern seals such as a Volvo or a Tides Marine, both of which use double lip seals. Volvo is simpler to fit, but not all stern tubes are the right OD whereas Tides cover a wider range of diameters. Make sure you get the right size imperial or Metric to suit your shaft.

 

[Bosun Higgs]

I've been trying to find out about the sizes of Volvo seals. Earlier in this thread someone says that they are available in imperial -= my concern is the reverse. My shaft is metric 25mm and I'm wondering if the tendency of the current Volvo to drip a bit is because its a one inch one. Anyone know which Volvo part number is which? The Volvo site is useless.

 

[Tranona]

I've been trying to find out about the sizes of Volvo seals. Earlier in this thread someone says that they are available in imperial -= my concern is the reverse. My shaft is metric 25mm and I'm wondering if the tendency of the current Volvo to drip a bit is because its a one inch one. Anyone know which Volvo part number is which? The Volvo site is useless.

Volvo seal is available in 25mm - as fitted to thousands of Beneteaus! Available from any Volvo dealer or Keyparts. Part No V 828254

 

[Squeaky]

Good morning:

In the end I discovered that Seaview in France and PYI in the US are experts in appearing to respond to e-mails without actually divulging much information. They turned out to be almost as expert as politicians in avoiding providing any direct information in reply to direct questions.

The correspondence finally ended with the following from PYI:
.....and in follow up to my previous email. This has gone on long enough and the seal was received from a dealer that sent you the seal and has absolutely nothing to do with PYI or SV Progress in EU. You have taken enough of my time and if you'd like to discuss anything further in regards to how this happened, why it happened or who's going to pay for xyz…contact the company that sold it to you on a go forward basis.

At no time did I request anyone to pay for the seals, I was only trying to determine if I had been supplied the correct items or if they had been locally sourced fakes but in the end I think the only thing I determined is that I was dealing with a bunch of fast talking used car salesmen who couldn't/wouldn't speak the truth under pain of death.

I would be happy to provide copies of the dozens of e-mails sent back and forth if anyone is interested - send me your e-mail address via a PM.

The theory behind the PSS might be okay but the product I was sold failed catastrophically after 20 and 100 hours of use and I was very fortunate not to have lost my yacht due to these failures.

I have installed a Volvo seal and have not used it enough to express an opinion but one thing is certain and that is that I would never, never again use or recommend a PSS seal if for no other reason than I don’t think the people behind it are ethical or willing to deal honestly with problems when they arise.

Cheers

Squeaky

P.S. Thankfully the Volvo seal is black and not Volvo green and I am trying to learn to ignore the fact that it was provided by Volvo.

 

[uxb]

That's not a good result Squeaky.
I've not long fitted a PSS seal and it was a bit of a faff getting the right size, mostly my fault. The first one that came had a glued in adapter to 'sleeve it down' to my shaft log size. It was a very loose sliding fit. This was swapped for a smaller end bellows that was a better fit.
I thought the service from them and more especially the boatyard, was excellent. locally, lots of folk have the PSS seal fitted and all of them are very happy with them and those that don't have the PSS have the Volvo seal( which isn't made in the size I require) Those two seals seem to be the default option now.

 

[Squeaky]

Good morning UXB

I think the problem with mine was the fact that the carbon piece that fit into the bellows was not long enough for the two jubilee clips to clamp to the carbon piece so that the aft clip was half on the carbon piece and half off which resulted in a "scissor like" pressure resulting in a cut to the bellows. I would not now secure the aft clip in the area moulded into the bellows but would move it forward nearer the forward clip to make real sure if was pressing the bellows against the carbon piece.

However I will never need to put this into practice as I wouldn't use a PSS if they gave one to me.

If it works and you are happy, go for it. They didn't work for me and the people behind it are not "correct" as they say in Newfoundland.

Cheers

Squeaky

 

[jakeroyd]

Read this thread with interest.
Apologies for slight drift.
I have a 25mm Volvo seal , now in it's 12th year (yes , I know Volvo reccomend replacement at 7 years)
It has never caused a moments problem.
I always burp it and I always feed it it's 1cc of Volvo grease every Spring.


Obviously I am pushing my luck with it's age , although many Forumites run Volvos well past 7years.
Obviously the 7 years is a very safe bet.
Mine has done comparatively little in terms of hours.

My musings were refecting on some of the comments about the PSS seal , the failure mode seems quite marked. In the sense that when they leak they leak badly.
It seems to me (an ex Land Rover transmissions engineer (no jokes about leaks please !)) that the Volvo seal will start to fail progressively because it uses lip seals with very substantial buffers to protect the seal lip from being damaged.
So maybe I can expect only a few drips to indicate times up for my seal (assuming the shaft material and surface finish are in spec and normal wear processes have taken place.)
Lip seals wear initially from almost a sharp lip to a land perhaps 0.25 wide and then stay stable.
In vehicles they do many magnitudes of rotations more than a Volvo seal but have perhaps better conditions.
Most Automotive seals pump a tiny amount of oil to the outside to keep the lip riding on an oil film.
Not sure if the Volvo does this.


How old are your Volvos and what failure mode/leak did you get to trigger a replacement ?

TIA

 

[vyv_cox]

In my opinion a Volvo seal is much safer than a PSS.I'd rather replace a worn shaft in order to fit a Volvo seal than use a face seal.

Every time the subject comes up there is a wealth of reported good experience with PSS seals. Some time ago I found a list of boat builders who fit PSS as original equipment - it was a couple of pages long. So your opinion may not count for very much. Not that I am knocking Volvo seals, I'm sure they are equally reliable but they do have disadvantages for some users.

 

[charles_reed]

Yes I do have the PSS seal and its the extra locking screws I am missing. Will try to get spare pair from supplier.

Website http://www.shaftseal.com/en/categories

I just sent an e-mail and some spares with an imperial-size Allen key arrived in the post from the US - extremely helpful people, I've had mine for 20 years and, apart from rope wraps forcing the rotor down the shaft, it's never leaked.
When it squeaks its usually running dry - if "burping" doesn't sort the problem you have usually got an obstruction preventing water getting up the stern-tube. The later variety, with a cooling tube from the carbon-block is usually less noisy.
They're probably not good for high-speed shafts >3000 rpm.

 

[30boat]

Every time the subject comes up there is a wealth of reported good experience with PSS seals. Some time ago I found a list of boat builders who fit PSS as original equipment - it was a couple of pages long. So your opinion may not count for very much. Not that I am knocking Volvo seals, I'm sure they are equally reliable but they do have disadvantages for some users.

My opinion counts to me and for that reason I wrote the words "in my opinion".From an engineering point of view the seal appears weak to me. All that stops water from coming in is the pressure the bellows exerts on the carbon piece.I know they don't usually leak and indeed I have fitted one to a friends boat over ten years ago that is still there happily sealing away.Still, I much prefer the Volvo seal simple solution and low price.

 

[RASilcock]

I had a leak problem with a pss I merely opened it up & found a few tiny shelled creatures cleaned the faces & OK lets a drop of water in but less than changing gland packing afloat,gives bilge pumps a test too. Rieaa.

 

[maxi]

Ignore 'boat30' and his advice to replace with a Volvo seal. If you have significant shaft movement the Volvo simply will not cope and will fail.

Don't take my word for it, read the Volvo installation info.

 

[Bosun Higgs]

I've used three types of seal so far. I used the original deep sea seal, a face seal like the PSS and one which gave trouble with small leaks. Plus I didnt like the way it stuck together and had to be freed before starting off. I then had an oil filled seal - a bronze tube bored to take three conventional lip seals and with an oil reservoir. That was excellent - cheap lip seal replace every couple of years and completely dry. Unfortunately no longer available.

Recently I have had Volvo seals which seem to last 2 years at the most before weeping but that could be my shaft which is 24.85 in the area where the seal sits.

 

[30boat]

Ignore 'boat30' and his advice to replace with a Volvo seal. If you have significant shaft movement the Volvo simply will not cope and will fail.

Don't take my word for it, read the Volvo installation info.

There was no advice whatsoever,merely an opinion based on experience.The fact is if there is a significant amount of movement either the installation is not a good one or there is something wrong with it.

 

[30boat]

I've used three types of seal so far. I used the original deep sea seal, a face seal like the PSS and one which gave trouble with small leaks. Plus I didnt like the way it stuck together and had to be freed before starting off. I then had an oil filled seal - a bronze tube bored to take three conventional lip seals and with an oil reservoir. That was excellent - cheap lip seal replace every couple of years and completely dry. Unfortunately no longer available.

Recently I have had Volvo seals which seem to last 2 years at the most before weeping but that could be my shaft which is 24.85 in the area where the seal sits.

If you're getting such short life from the Volvo seal then it must be because of the shaft diameter.Most seals stay bone dry mine included.

 

[Squeaky]

Good evening:

I had a very bad experience with two PSS seals - the first failed after 20 hours of use and the second after 100 hours and had I not refused an invitation to supper after returning to the marina my yacht would have been on the bottom when I returned.

I spent a lot of time trying to discover what caused these failures sending countless e-mails to the Seaview people in France and finally in frustration to the PYI (main seller of this seal) in the USA. I asked many questions trying to get to the bottom of the problem and feel I was fobbed off with misleading responses which did not deal with the questions I asked. I almost have the impression that the responses came from a list of stock replies which were mainly designed to encourage me to go away and stop bothering them. The final reply from PYI is shown above.

I have the impression that PYI and Seaview ship the various parts in bulk to the main dealers in each country and let them assemble the various items when an order is received. If the person who assemble/collects the various components does not know what he is doing or is careless the purchaser will receive components which are not matched. I suspect that this is what happened to my orders and that the carbon piece was intended for a smaller shaft and therefore shorter than it should have been. As the carbon piece was to short it did not extend far enough into the bellows and allowed a "scissor like" action from the aft jubilee clip which was clamped on to the bellows where indicated by the moulded marks on the bellows. In addition there was a "spacer" included which fit between the inside of the bellows and the carbon piece. This seems to indicate that the carbon piece was not large enough to fill the inside of the bellows which might indicate that the bellows was larger than it should have been. For example had the inside diameter of the bellows been correct there would have been no need for the spacer and the moulded indications where the clips were meant to be clipped would not have been as widely spaced as they were. A smaller bellows would have fit the carbon piece snugly and the moulded indicators for the clips would have been more appropriate for the length of the carbon piece.

I was requested to forward all the components to France so they could check it but later they used confusion about the measurements I provided from memory as an excuse for providing more misleading responses when they had the actual unit in their procession and could have measured it themselves without asking me for measurements. I had the impression that they were intent on creating as much confusion or misdirection as possible in order to encourage me to go away and stop bothering them. They certainly were not interested in getting to the bottom of the problem - I suspect they knew what had happened but did not want to admit it.

I believe I was sent mismatched components both times by the dealer in Istanbul and this was caused by the failure of PYI to assemble the correct components and box them for each of the various size of shafts and stern tubes leaving it for each dealer to assemble the components which means that an inexperienced or inattentive stock room employer could make a serious mistake.

Regardless of what happened I will certainly never use nor recommend this seal again. Anyone seriously interested in reading the correspondence for themselves have only to ask and I will forward all the messages that were exchanged and they can make up their own minds about the professionalism and ethics of PYI who sell this seal.

If any members are using this seal and are happy with its performance, all well and good but if you are thinking about purchasing one I suggest you think again.

Cheers

Squeaky

 

[vyv_cox]

If any members are using this seal and are happy with its performance, all well and good but if you are thinking about purchasing one I suggest you think again.

Cheers

Squeaky

I don't feel that your experience is typical and from my memory of it there is some doubt that what you bought was actually made by PSS. I bought mine from Aquafax in UK, where there was no doubt at all as to its manufacture, materials or construction.

 

[doug748]

I don't feel that your experience is typical and from my memory of it there is some doubt that what you bought was actually made by PSS. I bought mine from Aquafax in UK, where there was no doubt at all as to its manufacture, materials or construction.

Post 52 and 53 covers it.

 

[Old Troll]

PSS shaft seals

I feel that pss shafts seals are being totaly misrepresented by comments made and no bearing on what is an excellent product, provided that the genuine product is identified,purchased and fitted properly.

 

[ghostlymoron]

The Volvo seal is so much simpler and cheaper and apparently lasts much longer than the recommended 5 years. What's not to like?